Damage detection and warning system of a battery pack

ABSTRACT

An energy storage module for a vehicle includes an energy storage enclosure adapted to accommodate an energy storage cell, the energy storage enclosure having an enclosure wall, an optical sensor including an optical fiber, an optical receiver and an optical emitter, the optical fiber attached to an inner side of a first enclosure wall along a distance of a portion of the inner side. The optical receiver is configured to detect an optical signal transmitted through the optical fiber, and the optical sensor is configured to detect an alteration of the optical signal being indicative of a deformation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 15/171,536filed Jun. 2, 2016, now U.S. Pat. No. 10,276,901, which issued Apr. 30,2019, which claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to European patent application number EP 15171113.2, filedJun. 9, 2015, which are incorporated by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to an energy storage module, to an energystorage system, and to a method for assessing a deformation of an energystorage enclosure for an energy storage module.

BACKGROUND

Electric and hybrid vehicles have recently become a more common sight onroads worldwide. They have one thing in common and that is they allrequire a large and powerful rechargeable energy storage, also known asa battery. In most such batteries, several battery cells are stackedtogether to form a battery powerful enough to provide energy for thevehicle to drive for example several tens of kilometers. The batterycells are in most cases mechanically fixed together with a common frameor enclosure to form a single unit which is conveniently mounted in thevehicle. Furthermore, the size of a battery providing sufficient powerfor driving an electric or hybrid vehicle is relatively large, wherebythe battery cells tend to be closely packed in order to reduce the sizeof the battery.

The high powers of the batteries constitute a high risk, in particularfor passengers of the vehicle carrying the battery but also for thevehicle itself which may be damaged by a faulty battery. For example, incase of an accident causing an impact on the battery, a short circuitmay occur which may result in a fire. Another example is that an impactcaused by e.g. a rock may damage the battery in an unknown way. Forexample, the rock (or another object) may hit the battery from below thevehicle.

One example of an apparatus with an electronic sensor for detectingexternal physical impact is disclosed in US20060250262.

However, it is desirable to be able to more accurately assess the damagecaused by an external impact in order to better determine what actionsneed to be taken depending on the damage.

Therefore, there is a need for improved system for damage detection inbatteries for electric and hybrid vehicles.

SUMMARY

In view of the above, it is a general object of the present disclosureto provide improved damage detection in energy storage modules forvehicles, in particular for electric vehicles.

According to a first embodiment of the present disclosure there isprovided an energy storage module for a vehicle, the energy storagemodule comprising:

an energy storage enclosure adapted to accommodate at least one energystorage cell, the energy storage enclosure comprises at least oneenclosure wall; and

at least a first optical sensor comprising at least a first opticalfiber, at least a first optical receiver and an optical emitter, whereinthe optical fiber is attached to an inner side of at least a firstenclosure wall of the energy storage enclosure, the optical fiber isattached to the inner side along a distance of at least a portion of theinner side, the optical emitter being configured to emit an opticalsignal through the first optical fiber, and the optical receiver isconfigured to detect the optical signal transmitted through the firstoptical fiber,

wherein the optical sensor is configured to detect an alteration of theoptical signal, the alteration being indicative of a deformation of thefirst enclosure wall.

The present disclosure is based on the realization that an energystorage module, e.g. a battery pack, may be subjected to an impact whichmay damage the energy storage enclosure and thereby parts housed insidethe energy storage enclosure (e.g. energy storage cells, coolingsystems, printed circuit boards, etc.) without the user noticing thedamage. By continuing using the damaged energy storage module, moresevere accidents may occur. It is further realized that in case of anaccident, the energy storage module may be damaged in an unknown way. Inthat case there is a risk of improper handling of the energy storagemodule which could cause a hazardous situation for people handling thevehicle after the accident without being able to access the energystorage module. It is realized that by attaching an optical fiber to theinner side of the energy storage enclosure, a deformation of the energystorage enclosure may be detected by analyzing an optical signaltransmitted through the optical fiber. If the energy storage enclosureis in some way deformed, temporarily or permanently, the optical fiberbeing in contact with the energy storage enclosure in the region of thedeformation will also deform. The optical signal transmitted through thefiber will be altered as a result of the deformation, and thereby thealteration is an indication of the deformation of the energy storageenclosure. It is further realized that the optical fiber should bearranged on the inside of the energy storage enclosure in order to avoidor at least reduce the occurrence of false indications of deformationsdue to direct impact of external objects or forces on the optical fiber.Furthermore, another advantage of the present disclosure is that the useof optical sensors based on deformation of optical fibers eliminates orat least alleviates issues related to electromagnetic interference.

The energy storage enclosure should be understood as a housing which mayaccommodate energy storage cells suitable for providing power to anengine for providing propulsion to an electrical or hybrid vehicle. Theenergy storage cells may for example be Li-ion cells. The energy storagecells may be stacked in the energy storage enclosure. Optionally, theremay be cooling plates interleaved with the energy storage cells in thestack.

The “enclosure wall” may be any of a side wall, a top (e.g. the “lid”)of the enclosure, a bottom of the enclosure, or a bottom tray portion ofthe energy storage module. Thus, the term “wall” should be interpretedbroadly.

The inner side is the side of the energy storage enclosure wall facingin the direction of the energy storage cells if arranged in the energystorage enclosure.

The optical fiber is attached to an enclosure wall of the energy storageenclosure. For example, the optical fiber may be glued, or attached bymeans of adhesive tape, or any other adhesion method or product, or theoptical fiber may be attached using e.g. epoxy resin or a similarproduct as long as the optical fiber is deformed if attached in a regionwhere the enclosure wall is being deformed by a physical impact, e.g. anexternal force. Alternatively or additionally, the fiber may be coveredby e.g. foam, a plastic belt, or a metal sheet for fixation. The opticalfiber may be attached along a distance of at least a portion of theinner side to follow the surface of the inner side. This means that theoptical fiber is attached over a distance of the enclosure wall largerthan a point attachment. For example, the optical fiber may be attachedfrom a first end portion to second end portion of the first enclosurewall. The distance may for example cover the entire length of theenclosure wall, or only a few percent of the length of the enclosurewall, however, more than just a single point. By detecting an alterationof the optical signal transmitted through the optical fiber, adeformation of the enclosure wall may be detected. The optical fiber maybe for example a single core or multi-core optical fiber.

A deformation of an enclosure wall may be a change in the shape of theenclosure wall. For example, an impact by a rock or another object, orin case of an accident, there may be a local change in the shape at thelocation of the impact. Thus, a deformation is an alteration of theform, geometry, cross-section, or shape of the enclosure wall, and/orthe deformation may be an intrusion on the enclosure wall.

The optical emitter is a device arranged to emit light, for example, theoptical emitter may comprise a light-emitting diode, a laser, or anothersolid state light source. The optical receiver may be a device capableof converting light into an electronic signal. For example, an opticalreceiver may be a photodetector.

According to an embodiment of the disclosure, the energy storage modulemay further comprise a second optical sensor comprising a second opticalfiber attached to the same first enclosure wall as the first opticalfiber and spaced apart from the first optical fiber, and a secondoptical receiver configured to detect an optical signal transmittedthrough the second optical fiber, wherein the second optical sensor isconfigured to detect an alteration of the optical signal transmittedthrough the second optical fiber. By attaching a second fiber to thesame enclosure wall, it is possible to more accurately locate adeformation of the enclosure by determining in which of the fibers analteration of the optical signal is detected and relating the opticalfibers to their locations on the enclosure walls.

According to an embodiment of the disclosure, the energy storage modulemay further comprise a second optical sensor comprising a second opticalfiber attached to an enclosure wall of the energy storage enclosuredifferent from the enclosure wall which the first optical fiber isattached to, and a second optical receiver configured to detect anoptical signal transmitted through the second optical fiber, wherein thesecond optical sensor is configured to detect an alteration of theoptical signal transmitted through the second optical fiber. In thisway, it is possible to determine which enclosure wall is deformed.

According to an embodiment of the disclosure, each of the opticalfiber(s) may have a respective optical receiver and a respective opticalemitter. For example, the second optical sensor may comprise an opticalemitter. The optical sensor may be more robust and less sensitive todamages by providing each fiber with its own optical receiver andoptical emitter.

One optical emitter may be arranged to emit light through more than oneoptical fiber, and wherein each optical fiber has a respective opticalreceiver. For example, the first and the second optical sensors mayshare an optical emitter.

The alteration of an optical signal may be an alteration of an opticaltransmission property of a respective one of the optical fiber(s). Forexample, if the optical fiber is bent, or in other ways deformed, theoptical path through the optical fiber is altered. Thereby thetransmission of the optical signal is altered and may be detected by theoptical sensor.

According to an embodiment of the disclosure, the optical sensors may beconnected to a control unit, wherein the control unit may be configuredto determine a magnitude and/or a location of the deformation of theenclosure wall based on the detected alteration of an optical signal.Thus, the control unit may relate the detected alteration to a magnitudeof the deformation of the enclosure wall. For this reason, an alteredoptical transmission may be related through experimental data to theamount of deformation of the optical fiber. For example, there may be apredetermined data set of bending radius of the optical fiber versus afraction of light loss through the optical fiber. Alternatively oradditionally, there may be a predetermined data set of pressing force(or pressure applied, or amount of compression of) applied to theoptical fiber versus a fraction of light loss. The pressure or pressingforce causes the fiber to be compressed which result in an amount ofcompression of the fiber which causes that less light is allowed to passthrough the fiber. In a similar way, bending of the optical fiber causesthat less light is allowed to pass through the fiber. Alternatively oradditionally, the control unit may relate the detected alteration to alocation of the deformation of the enclosure wall. Note that the“location” may relate to a location/region on an enclosure wall, or“location” may also relate to which of the enclosure walls has beendeformed.

According to an embodiment of the disclosure, the control unit may beconfigured to determine a severity of an impact based on the detectedalteration of any of the optical signals. The control unit may determinefrom a combination of the magnitude of the deformation and the locationof the deformation, a degree of severity. For example, a relativelysmall deformation may not be determined as having a high degree ofseverity, or a deformation in a less sensitive region (e.g. a region notin close proximity to an energy storage cell) of the energy storagemodule may not be determined as having a high degree of severity.Furthermore, a deformation in a sensitive region of the energy storageenclosure may be determined to be severe, or a relatively largedeformation may be determined to be severe. A combination of location ofthe deformation and the magnitude of the deformation may also be used todetermine the severity of the deformation.

According to an embodiment of the disclosure, the severity may bedetermined based on determining a location of a deformation of anenclosure wall, wherein the location is determined by relating adetected alteration of an optical signal transmitted through any of theoptical fibers to the location of the respective optical fiber.

The severity may be determined based on a magnitude of the deformationof the enclosure wall, where the magnitude is determined by relating thealteration of the optical signal through an optical fiber to adeformation of a respective optical fiber.

According to a second embodiment of the disclosure there is provided anenergy storage system comprising an energy storage module according toany one the preceding embodiments, and further comprising the controlunit.

According to an embodiment of the disclosure, the control unit may beconfigured to transmit a warning signal to a user interface in case theseverity exceeds a threshold. The user interface may for example be partof the control panel inside the vehicle (e.g. a head-up display), or itmay be part of an external device connected to the control unit. Theexternal device may for example be useful if the vehicle was subjectedto an accident. The warning signal may inform the driver of thedeformation and instruct the driver to immediately pull over and turnoff the vehicle, or the warning signal may instruct the driver toproceed to a service station for maintenance. The warning signal may bea sound signal or a visual signal/indicator, or a combination, forexample shown on a head-up display.

The control unit may be one of: control unit of a supplement restraintsystem (SRS) for a vehicle or battery management system control unit ofthe energy storage module. Of course control units of other parts of thevehicle may also function for the purpose of this disclosure.

Further effects and features of this second embodiment of the presentdisclosure are largely analogous to those described above in connectionwith the first embodiment of the disclosure.

According to a third embodiment of the disclosure there is provided amethod for assessing a deformation of an energy storage enclosure for anenergy storage module, the deformation being caused by an externalforce, the energy storage enclosure comprising at least a firstenclosure wall, wherein an optical fiber is attached to the firstenclosure wall, the method comprising the steps of:

monitoring the transmission of an optical signal transmitted through theat least one optical fiber,

determining an alteration of the optical signal, the alteration beingindicative of a deformation of the first enclosure wall; and

According to an embodiment of the disclosure, the method may furthercomprise: based on the alteration of the optical signal, determining aseverity of an impact on the energy storage module.

if the severity exceeds a threshold value, providing a warning messageto a user.

Further effects and features of this third embodiment of the presentdisclosure are largely analogous to those described above in connectionwith the first and the second embodiments of the disclosure.

The energy storage cell(s) may be Li-ion battery cell(s).

The control unit may comprise one or more processors, microprocessors,microcontrollers, programmable digital signal processors or otherprogrammable devices, which may include memory. The control unit mayalso, or instead, comprise an application specific integrated circuit, aprogrammable gate array or programmable array logic, a programmablelogic device, or a digital signal processor. Where the control unitcomprises a programmable device such as a processor, microprocessor,microcontroller or programmable digital signal processor mentionedabove, the control unit may further comprise computer executable codestored in memory that when executed controls operation of the controlunit and/or performs the functions and/or operations described herein.

There is further provided a vehicle comprising the energy storagemodule. The vehicle may be an electric or hybrid vehicle.

Further features of, and advantages with, the present disclosure willbecome apparent when studying the appended claims and the followingdescription. The skilled person realizes that different features of thepresent disclosure may be combined to create embodiments other thanthose described in the following, without departing from the scope ofthe present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described in more detail, withreference to the appended drawings showing various embodiments of thedisclosure, wherein:

FIG. 1a schematically shows an example application for an exampleembodiment of an energy storage module;

FIG. 1b illustrates an example energy storage cell;

FIG. 1c illustrates an example stack of energy storage cells and coolingplates;

FIG. 2a shows an example energy storage enclosure with optical sensors;

FIG. 2b shows an example energy storage module according to anembodiment of the present disclosure;

FIG. 3 shows a partial view of an example energy storage enclosure withoptical sensors;

FIG. 4 provides a flow-chart of method steps according to an embodimentof the disclosure; and

FIG. 5 shows example data relating loss of light in an optical fiber tothe intrusion in the energy storage enclosure.

DETAILED DESCRIPTION

As required, detailed embodiments are disclosed herein. However, it isto be understood that the disclosed embodiments are merely exemplary andthat various and alternative forms may be employed. The figures are notnecessarily to scale. Some features may be exaggerated or minimized toshow details of particular components. Therefore, specific structuraland functional details disclosed herein are not to be interpreted aslimiting, but merely as a representative basis for teaching one skilledin the art.

In the following description, the present disclosure is mainly describedwith reference to an energy storage module for an electric or hybridvehicle in the form of a car. However, the disclosure may be applied toany type of electric or hybrid vehicle such as a truck, a fork lift, aboat, etc.

FIG. 1a illustrates an electric vehicle 1 comprising an energy storagemodule 100. The energy storage module 100 (300) is configured to providepower for operating the electric vehicle 1, thus the energy storagemodule 100 (300) may be arranged to provide power to an electric motorfor providing propulsion for the electric vehicle 1. The electricvehicle 1 is depicted as an electric car, however any other vehicle,such as e.g. a truck is also suitable. The energy storage module 100(300) of this electric vehicle 1 may be an energy storage module 100(300) according to example embodiments of the present disclosure. Thereis further a control unit 102 or 102′ which may either be part of thebattery management system (control unit 102) of the energy storagemodule 100, or be a control unit of a supplement restraint system 102′of the vehicle 1. The function of the control unit 102 or 102′ inaccordance with embodiments of the disclosure will be described withreference to subsequent drawings.

FIG. 1b illustrates an example of an energy storage cell 202 (203, 204).The energy storage cell 202 is planar and has a main extension in aplane 104. The energy storage cell 202 has a surface portion 212 and anedge portion 103 around the perimeter of the planar energy storage cell202. The energy storage cell may thus comprise two opposite surfaceportions 212, 212′ interconnected by the edge portion 103.

FIG. 1c illustrates energy storage cells 202, 203, 204 stacked in astacking direction 219 as an example arrangement of energy storagecells. There is also cooling plates 210 interleaved with the energystorage cells 202-204, and optionally end plates 306, 307 at the ends ofthe stack.

FIG. 2a illustrates an energy storage enclosure 110 adapted toaccommodate energy storage cells 202-204. Inside the energy storageenclosure 110, there is more than one optical fiber 112 (112′, 112″)attached to the inner side 114 of one of the enclosure walls 120. Eachof the optical fibers 112 has a respective optical emitter 116 (not allare visible, not all are numbered) configured to emit an optical signalinto the respective optical fiber 112. There is further an opticalreceiver 118 (not all are visible, not all are numbered) arranged toreceive and detect the optical signal at the output side of the opticalfiber 112, after the optical signal has been transmitted through theoptical fiber 112. An optical fiber 112, an optical emitter 116 and anoptical receiver 118 together form an optical sensor 111 (not all arenumbered). The energy storage enclosure 110 will now be described aspart of an example energy storage module 300.

FIG. 2b illustrates an energy storage module 300 (100) according to anexample embodiment of the disclosure. The energy storage module 300comprises an enclosure 110 (also shown in FIG. 2a ) having arrangedtherein energy storage cells 202-204. Thus, the enclosure 110accommodates the energy storage cells 202-204. In this exampleembodiment, the enclosure 110 accommodates several energy storage cells202, 203, 204 arranged in parallel (thus the respective planes 104 aresubstantially parallel with each other), and optionally also coolingplates 210. There may further be other parts which are not shown thatmay be part of the energy storage module, for example, partsinterconnecting energy storage cells and cooling plates such as plasticframes, foam, steel/plastic end plates and etc. For example, there maybe end plates 306, 307 arranged at the end of the stack of energystorage cells 202-204. In FIG. 2b , the energy storage cells 202, 203,204, and the cooling plates 210 are stacked in a stacking direction 219as is illustrated in the exploded view in FIG. 1c . The energy storagecells 202, 203, 204 may be Li-ion battery cells.

Furthermore, in FIG. 2b there are also shown optical sensors 111 (seeFIG. 2a ) each comprising an optical fiber 112, an optical emitter 116,and optical receivers 118. The optical fibers 112 are attached to theinner side 114 of an enclosure wall 120 along a distance from a firstend portion 230 to a second end portion 231 of the enclosure wall 120.The optical fibers 112 may be e.g. glued to the enclosure wall 120 orattached to the enclosure wall 120 using an adhesive tape. Alternativelyor additionally, the fiber 112 may be covered by e.g. foam, a plasticbelt, or a metal sheet for fixation. The optical fibers 112 are attachedto the enclosure wall 120 such that if the enclosure wall is deformed ata location of the optical fiber 112, the optical fiber 112 will also bedeformed and thus follow the deformed shape of the enclosure wall 120.The optical emitters 116, each which may be a solid state laser orlight-emitting diode, are each configured to emit an optical signalthrough the respective optical fiber 112. The optical receivers 118 areconfigured to receive and detect the optical signal transmitted throughthe respective optical fiber 112. The optical signal may have awavelength in the range of e.g. 1.3 μm to 1.55 μm although otherwavelengths may be appropriately chosen and is not limiting to thedisclosure. If the optical fiber 112 is deformed, for example bent, theoptical transmission through the optical fiber is altered. An examplefunction of loss of light versus the amount of intrusion of an energystorage enclosure causing a deformation of an optical fiber is shown inFIG. 5. This type of data (loss of light versus intrusion which isrelated to the amount of deformation of the optical fiber) may bepredetermined and later used for predicting a deformation of anenclosure wall based on the detected optical signal. For example, theoptical transmission may be decreased (e.g. attenuation of thetransmitted optical signal due to for example increased losses in theoptical fiber) or the time of flight of the optical signal through theoptical fiber may be altered. Thereby, if the enclosure wall 120 isdeformed in a location where the optical fiber 112 is attached, theoptical fiber 112 will be deformed accordingly and thus the opticalsignal through the optical fiber 112 will be altered. In this way, thedeformation of the enclosure wall 120 may be detected.

In that regard, for such detection, the optical sensors described hereinmay further comprise one or more processors, microprocessors,microcontrollers, programmable digital signal processors or otherprogrammable devices, which may include memory. The optical sensors mayalso, or instead, comprise an application specific integrated circuit, aprogrammable gate array or programmable array logic, a programmablelogic device, or a digital signal processor. Where the optical sensorscomprise a programmable device such as a processor, microprocessor,microcontroller or programmable digital signal processor mentionedabove, the optical sensors may further comprise computer executable codestored in memory that when executed controls operation of the opticalsensors and/or performs the functions and/or operations describedherein.

As shown in the embodiment of FIG. 2.b (also seen in FIG. 2a ), there ismore than one optical fiber 112 attached to the inner side 114 of theenclosure wall 120. For example, there is a second optical fiber 112″attached to the enclosure wall spaced apart from a first optical fiber112′. In this embodiment, the first optical fiber 112′ and the secondoptical fiber 112″ has a respective optical emitter 116′, 116″ andoptical receiver 118′, 118″. However, it would be possible for opticalfibers 112′, 112″, and the optical receivers 118′, 118″ to share asingle optical emitter 116′ or 116″ by guiding the optical signal fromthe emitter to both the optical fibers 112′, 112″. By individuallydetecting alterations of optical signals transmitted through the first112′ and the second optical fiber 112″, a location of a deformation ofthe enclosure wall 120 may more accurately be determined. For example,it is possible to have knowledge of the location of the optical fibers112′, 112″, e.g. the first optical fiber 112′ is arranged in a firstregion/location 134 and the second optical fiber is arranged in a secondregion/location 136 of the enclosure wall 120. If an alteration of theoptical signal through the second optical fiber 112″ is detected, it maybe determined that the deformation is in the second region 136.Furthermore, there may be optical fibers having respective opticalreceivers and optical emitters arranged on enclosure walls (e.g.enclosure wall 138, or any of the other enclosure walls, not numbered)other than the first enclosure wall 120. Thereby, it is possible todetermine which of the enclosure walls has been deformed.

Although depicted in the embodiments that each of the optical fibers 112has a respective optical receiver 118 and a respective optical emitter116, it may be possible that an optical emitter provides an opticalsignal for more than one optical fiber, e.g. two optical fibers mayshare a single optical emitter.

An optical fiber 112 in the embodiments may be single core or multiplecore optical fiber known in the art. For example, the optical fiber 112may be made from quartz glass or plastic material. The core of a singlecore optical fiber may be e.g. 8 μm to 12 μm. The optical signal may beconstant (e.g. continuous) or modulated in intensity. The optical signalmay be constant in intensity.

The optical sensor(s) 111 may be connected to a control unit 102, 102′which may be one of an control unit of a supplement restraint system102′ of the vehicle in which the energy storage module 300 is arranged,or the control unit may be a control unit 102 of the energy storagemodule itself (e.g. part of the battery management system). The controlunit (e.g. a microprocessor) may together with the energy storage moduleform an energy storage system 400 according to an embodiment of thedisclosure.

The control unit 102, 102′ is configured to determine a severity of animpact on the energy storage enclosure 110 based on the detectedalterations of optical signals transmitted through optical fibers. Theseverity may be determined to be e.g. “low”, “medium”, or “high” (otherclassifications are of course possible) based on one of the magnitude ofa deformation or a location of the deformation, or a combination ofmagnitude and location of the deformation. For example, if it isdetermined that the intrusion on the energy storage enclosure (sensed bydetecting the alteration in the optical signal resulting from e.g. abending radius on the fiber or an amount of compression on the fiber) ofthe optical fibers 112 exceeds a high threshold the severity may bedetermined to be “high” and a warning message may then instruct thedriver via a user interface 240 to immediately pull over and turn offthe vehicle. A high threshold may be in the range 12 mm to 30 mm or anynumber in that range, e.g. 15 mm, 18 mm, 20 mm, or 25 mm. If theintrusion does not exceed the high threshold, but only a mediumthreshold, the severity may be “medium” and the driver may be instructedto drive to the nearest service station. A medium threshold may be inthe range 6 mm to 20 mm or any number in that range, e.g. 8 mm, 10 mm,12 mm, or 15 mm. If the intrusion does not exceed the medium thresholdor alternatively a lower threshold (e.g. “low”), there will be nowarning message. The description herein of the severity levels of“high”, “medium”, and “low” only serve as an example and otherdefinitions may of course be possible. Furthermore, the severity alsodepends on the location of the deformation (or intrusion). For example,a small intrusion in a sensitive location (e.g. close to sensitive partsof the energy storage module) may also result in a “high” severity. Inother words, the severity depends on both the amount of intrusion and onthe location of the intrusion. It is equally applicable to comparevoltage signals from the optical sensors to voltage thresholds in orderto determine the severity. Furthermore, it may be known where in theenergy storage module 300 sensitive parts are placed. Thus, if it isdetermined that a deformation occurred in a region close to thesensitive parts, a higher severity may be determined than if thedeformation occurred in a region not close the sensitive parts.Sensitive parts may be e.g. elements of the cooling system (e.g. pipes)of high voltage components on e.g. printed circuit boards, and/or theenergy storage cells. The control unit 102, 102′ together with theenergy storage module 300 form an energy storage system 400.

FIG. 3 shows a partial view of an energy storage enclosure 110 havingseveral optical sensors 111, 111 a-b arranged therein. Each of theoptical sensors 111 has an optical fiber 112, an optical emitter 116,and an optical receiver 118. In this view of the energy storageenclosure 110 there is shown a first 120 and a second energy storageenclosure wall 138. The second wall 138 may for example be a bottom wallof the energy storage enclosure 110. Furthermore, the energy storageenclosure 110 has been exposed to external forces; thereby a deformation140 has been formed on both the first 120 and the second wall 138. Thedeformation 140 causes a local alteration of the shape/form of therespective wall 120, 138. Furthermore, there is an optical fiber 112 a,112 b attached to the enclosure walls at the locations of thedeformations 140. Since the optical fibers 112 a-b are attached suchthat they are also deformed as a result of the deformed enclosurewall(s) 120, 138, the optical transmission properties are altered in theoptical fibers 112 a-b attached at the deformations. For example, theoptical fibers 112 a-b attached to the enclosure wall 120, 138 at thedeformations 140 (the optical fibers extending across the deformations)are bent or pressed in the part of the optical fiber 112 a-b near and atthe deformation. The optical transmission properties are modified as aresult of the bending (or pressing) of the optical fiber 112 a-b, andthereby the deformation may be detected as described with reference tothe previous drawings. Furthermore, by relating the optical sensor 111a, 111 b (or the respective optical fiber 112 a-b) which detected adeformation to the enclosure wall where it is arranged (i.e. to whichwall the respective optical fiber is attached), it is possible to locatethe deformation in terms of which enclosure wall 120, 138 is deformed.Furthermore, by relating the location of the optical fiber 112 a-b onthe enclosure wall, it is possible to determine in which region of theenclosure wall the deformation occurred. This may be used to determineat least partly the severity of the deformation.

FIG. 4 provides a flow-chart with method steps according to anembodiment of the disclosure. The method is for assessing a deformationof an energy storage enclosure for an energy storage module. The energystorage enclosure comprises at least a first enclosure wall. Furthermorean optical fiber is attached to the first enclosure wall. Firstly S402,the transmission of an optical signal transmitted through the at leastone optical fiber is monitored. Subsequently, in step S404 an alterationof the optical signal is determined/detected. Based on the alteration ofthe optical signal, a severity of an impact on the energy storage modulemay be determined S406. Furthermore, if the severity exceeds a thresholdas determined in step S408, a warning message may be provided S410 to auser. The warning message may be provided via a user interface of avehicle using the energy storage module, or via an external deviceconnected to a control unit of the vehicle. The warning message may bein the form of a visual message (e.g. picture or text) or via a soundsignal/message.

Additionally, variations to the disclosed embodiments can be understoodand effected by the skilled person in practicing the claimed disclosure,from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality. The mere fact that certain measures are recited in mutuallydifferent dependent claims does not indicate that a combination of thesemeasured cannot be used to advantage.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the disclosure. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the disclosure.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the disclosure.

What is claimed is:
 1. A method for assessing a deformation of an energystorage enclosure for an energy storage module, the deformation beingcaused by an external force, the energy storage enclosure configured toaccommodate an energy storage cell and comprising an enclosure wall andan optical sensor comprising an optical receiver and an optical emitter,wherein an optical fiber is attached to an inner side of the enclosurewall of the energy storage enclosure along a distance of a portion ofthe inner side, the method comprising: monitoring transmission of anoptical signal transmitted through the optical fiber, wherein monitoringcomprises transmitting, via the optical emitter, an optical signalthrough the optical fiber and receiving, via the optical receiver, theoptical signal transmitted through the optical fiber; determining analteration of the optical signal, the alteration being indicative of adeformation of the enclosure wall, wherein determining comprisesdetecting, via the optical sensor, the alteration of the optical signal;based on the alteration of the optical signal, determining a severity ofan impact on the energy storage module, wherein the severity of theimpact is based on magnitude of the impact or a location of the impact;and in response to the severity of the impact exceeding a thresholdvalue, providing a warning message to a user.
 2. The method according toclaim 1 wherein the energy storage enclosure further comprises a secondoptical sensor comprising a second optical fiber attached to theenclosure wall and spaced apart from the optical fiber, and a secondoptical receiver configured to detect an optical signal transmittedthrough the second optical fiber, the method further comprising:transmitting an optical signal through the second optical fiber;receiving, via the second optical receiver, the optical signaltransmitted through the second optical fiber; and detecting, via thesecond optical sensor, an alteration of the optical signal transmittedthrough the second optical fiber.
 3. The method according to claim 1further comprising a second optical sensor comprising a second opticalfiber attached to another enclosure wall of the energy storage enclosuredifferent from the enclosure wall to which the optical fiber isattached, and a second optical receiver configured to detect an opticalsignal transmitted through the second optical fiber, the method furthercomprising: transmitting an optical signal through the second opticalfiber; receiving, via the second optical receiver, the optical signaltransmitted through the second optical fiber; and detecting, via thesecond optical sensor, an alteration of the optical signal transmittedthrough the second optical fiber.
 4. The method according to claim 2wherein the second optical sensor comprises an optical emitter.
 5. Themethod according to claim 2 wherein the second optical sensor shares theoptical emitter of the optical sensor.
 6. The method according to claim1 wherein the alteration of an optical signal is an alteration of anoptical transmission property of the optical fiber.
 7. The methodaccording to claim 1 wherein the optical sensor is connected to acontrol unit, the method further comprising determining, via the controlunit, the magnitude or the location of the deformation of the enclosurewall based on the detected alteration of the optical signal.
 8. Themethod according to claim 7 wherein determining the severity theseverity of the impact comprises determining, via the control unit, theseverity of the impact based on the detected alteration of the opticalsignal.
 9. The method according to claim 8 wherein determining theseverity of the impact comprises determining, via the control unit, thelocation of a deformation of an enclosure wall by relating the detectedalteration of the optical signal transmitted through the optical fiberto the location of the optical fiber.
 10. The method according to claim8 wherein determining the severity of the impact comprises determining,via the control unit, the magnitude of the deformation of the enclosurewall by relating the detected alteration of the optical signaltransmitted through the optical fiber to a deformation of the opticalfiber.
 11. The method according to claim 8 wherein providing the warningmessage to the user comprises transmitting, via the control unit, thewarning message to a user interface in response to the severityexceeding the threshold value.
 12. The method according to claim 9wherein providing the warning message to the user comprisestransmitting, via the control unit, the warning message to a userinterface in response to the severity exceeding the threshold value. 13.The method according to claim 10 wherein providing the warning messageto the user comprises transmitting, via the control unit, the warningmessage to a user interface in response to the severity exceeding thethreshold value.